Hinge assembly for flat panel display appliance

ABSTRACT

Disclosed is a hinge assembly capable of adjusting a tilting angle of a display in a display appliance. The hinge assembly includes a movable plate fixed to a rear side of the display and having a through-hole, a stationary plate coupled to a stand for the display appliance and having a through-hole, a hinge shaft passing through the through-holes of the movable and stationary plates and having a head portion, a coupling member fixed to one end of the hinge shaft, a first washer disposed between the head portion of the hinge shaft and the movable plate, first and secondary washers disposed at both sides of the through-hole of the movable plate, and third and fourth stationary washers disposed at both sides of the through-hole of the stationary plate. At least one of the first, second, third and fourth stationary washes is an elastic washer for applying compressive elasticity to the hinge shaft in an axial direction.

TECHNICAL FIELD

[0001] The present invention relates to a hinge assembly capable ofadjusting a tilting angle of a display in a flat panel displayappliance, and more particularly, to a hinge assembly adapted to beeasily assembled using a common bolt as a hinge shaft of a rotationaround which a display is pivoted, without separately machining thehinge shaft.

BACKGROUND ART

[0002] Generally, a hinge assembly for a display appliance used in apersonal computer includes, as shown in FIG. 1, an L-shaped mountingplate 3 having a vertical portion 3 b formed with a hinge shaftreceiving hole and a horizontal portion 3 c at one side secured to acasing body of the display appliance; and a hinge shaft 1 having amounting portion 1 a secured to an upper cover of a casing of thedisplay appliance, an extended portion 1 c at the other side pivotallyinserted into the hinge shaft receiving hole of the mounting plate 3,and a flange 1 b between the mounting portion and the extended portion.The extended portion 1 c has at a free end thereof a faceted portion 1c′ with a threaded portion formed thereon.

[0003] The hinge assembly also includes washers 2 a and 2 b disposed atboth ends of the mounting plate, an axially biased resilience washer 4,a sleeve member 5 contacted with the resilience washer 4, a torsionspring 6, a washer 7 restricting a pivoting range and having a stopperboss 7 a, and a nut 8.

[0004] The sleeve member 5 has a flange portion 5 a contacted with theresilience washers 4 and a tubular portion 5 b receiving the torsionspring 6 therein. The torsion spring has one bent end 6 a inserted intoa hole 3 a formed at the vertical portion 3 b of the mounting plate, andthe other end supported by the stopper boss 7 a of the washer 7.

[0005] The pivot range restricting washer 7 is formed with a hole havinga shape corresponding to that of the faceted portion 1 c′ of theextended portion 1 c. Since the faceted portion 1 c′ is inserted intothe hole, when the hinge shaft is pivoted in one direction, the pivotrange is restricted until the braking boss 7 a reaches to the end 6 a ofthe torsion spring 6. When the hinge shaft is pivoted in the counterdirection, the washer 7 is applied with elasticity against the pivotingoperating, since the braking boss 7 a is stopped by the other end of thetorsion spring.

[0006] Since the hinge assembly as described above requires thespecially faceted hinge shaft, the hinge shaft has to be machinedthrough a faceting process including milling and turning during themanufacturing of the hinge assembly, thereby increasing themanufacturing cost. In addition, separate components corresponding tothe shape of the faceted hinge shaft must be manufactured, therebycomplicating the design of the hinge assembly and making difficult toassemble the hinge. Furthermore, there is another problem in that therelatively soft plate of the components of the hinge assembly can beeasily worn by the rotation of the hinge shaft.

DISCLOSURE OF THE INVENTION

[0007] Therefore, an object of the present invention is to solve theproblems involved in the prior art, and to provide a hinge assemblyadapted to be easily assembled using a common bolt without separatelymachining a hinge shaft of a basic axis around which a display ispivoted.

[0008] Another object of the present invention is to provide a hingeassembly in which stationary and movable plates are not worn duringrotation.

[0009] Another object of the present invention is to provide a hingeassembly capable of adjusting a tilting angle of a display without usinga separate component assembled which is a faceted hinge shaft so as torestrict a pivoting range of the hinge shaft.

[0010] Another object of the present invention is to provide a pivotassembly which has excellent pivotable performance and is capable ofbeing easily assembled and reducing the manufacturing cost thereof.

[0011] In order to accomplish the above mentioned objects, the presentinvention provides a hinge assembly for adjusting a tilting angle of adisplay for a flat panel display appliance, comprising: a movable platefixed to a rear side of the display and having a through-hole; astationary plate coupled to a stand of the display and having athrough-hole; a hinge shaft passed through the through-holes of themovable and stationary plates and having a head portion; a couplingmember fixed to one end of the hinge shaft; a first washer disposedbetween the head portion of the hinge shaft and the movable plate; firstand second stationary washers disposed at both sides of the through-holeof the movable plate; and third and fourth stationary washers disposedat both sides of the through-hole of the stationary plate; wherein atleast one of the first, second, third and fourth stationary washes is anelastic washer for applying compressive elasticity to the hinge shaft inan axial direction.

[0012] According to one preferred embodiment of the present invention,the through-hole of the stationary plate is opened at an upper portionthereof.

[0013] According to one preferred embodiment of the present invention,the movable plate has a bent boss at an upper end of the through-hole,and the stationary plate has a pivot guide at an upper end of thethrough-hole, the bent boss of the movable plate moving along a passagepivoting about the hinge shaft.

[0014] According to one preferred embodiment of the present invention,the movable plate has a latching groove formed at a portion parallel tothe hinge shaft, and a coil spring with one end fixed to the latchinggroove of the movable plate and the other end inserted into a fixinghole formed at the stationary plate, the coil spring applying aresistant force against a pivoting direction of the movable platerelative to the stationary plate around the hinge shaft.

[0015] According to one preferred embodiment of the present invention,the first, second, third and fourth stationary washers have at least onefixing boss, and the movable and stationary plates are formed with afixing hole adjacent the through-hole thereof for receiving the fixingboss of the stationary washer.

[0016] According to one preferred embodiment of the present invention,any one of the third and fourth stationary washers has an upper fixingboss of a width slightly smaller than that of the opened portion of thethrough-hole of the stationary plate, and the fixing hole of thestationary plate for receiving the upper fixing boss is the openedportion of the through-hole.

[0017] According to one preferred embodiment of the present invention,the hinge shaft has an axially extended portion with a threaded portionformed thereon, and a head portion larger in diameter than the extendedportion.

[0018] According to one preferred embodiment of the present invention,the hinge shaft is a commonly used bolt.

[0019] According to one preferred embodiment of the present invention,the coupling member is a nut.

[0020] According to one preferred embodiment of the present invention,the first washer is a flat washer.

[0021] According to one preferred embodiment of the present invention,the first washer has an oil impregnating groove for preventing wear of acontacted portion between the washers and an adjacent component and forsecuring smooth pivoting movement.

[0022] According to one preferred embodiment of the present invention,at least one of the stationary washers has an oil impregnating groovefor preventing wear of a contacted portion between the washers and anadjacent component and for securing smooth pivoting movement.

[0023] According to one preferred embodiment of the present invention,the elastic washer is a hemispheric washer having a fixing boss fixed tothe plate.

[0024] According to one preferred embodiment of the present invention,the elastic washer is a stationary washer fixed to the stationary plateand disposed adjacent to the coupling member, and the coupling member isa washer-type nut.

[0025] It is to be understood that both the foregoing generaldescription and the following detailed description of the presentinvention are exemplary and explanatory and are intended to providefurther explanation of the present invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above objects, other features and advantages of the presentinvention will become more apparent by describing the preferredembodiment thereof with reference to the accompanying drawings, inwhich:

[0027]FIG. 1 is an exploded view showing a conventional hinge assemblyfor a flat panel display appliance;

[0028]FIG. 2 is a perspective view of a hinge assembly for a flat paneldisplay appliance according to one preferred embodiment of the presentinvention;

[0029]FIG. 3 is an exploded view of the hinge assembly of FIG. 2;

[0030]FIG. 4 is a perspective view of a hinge assembly according toanother preferred embodiment of the present invention, in which a coilspring is installed;

[0031]FIG. 5 is an exploded view of the hinge assembly of FIG. 4;

[0032]FIG. 6 is a perspective view of a hinge assembly according toanother preferred embodiment of the present invention, in which astationary plate having a through-hole of which an upper portion isopened is employed;

[0033]FIG. 7 is an exploded view of the hinge assembly of FIG. 6;

[0034]FIG. 8 is a perspective view of a hinge assembly according toanother preferred embodiment of the present invention of FIG. 6, inwhich a coil spring is additionally installed; and

[0035]FIG. 9 is an exploded view of the hinge assembly of FIG. 8.

BEST MODE FOR CARRYING OUT THE INVENTION

[0036] Reference will now be made in detail to the preferred embodimentsof the present invention; examples of which are illustrated in theaccompanying drawings. In the embodiments, like parts are shown bycorresponding reference numerals throughout the drawings, and additiveexplanation thereof will be omitted.

[0037]FIG. 2 shows a perspective view illustrating the assembled stateof a hinge assembly for a flat panel display appliance according to onepreferred embodiment of the present invention, in which a coil spring iseliminated. FIG. 2 shows only one side of the hinge assembly. Eventhough the hinge assembly of the present invention may be installed atone side of the flat panel display appliance, as shown in FIG. 2, it ispossible to adjust the tilting angle of the display of the flat paneldisplay, without installing another hinge assembly having the sameconstruction as the hinge assembly.

[0038] As shown in FIG. 2, the hinge assembly 100 of the presentinvention includes a hinge member A having a movable plate 10 fixed to arear side of a display of a flat panel display appliance for securingthe hinge member A, and a stationary plate 20 coupled to a standsupporting the display against a certain bottom and disposed adjacent tothe movable plate to cause the movable plate to be rotated. The term“movable” in the movable plate means that the movable plate can berotated relative to the stationary plate. The term “stationary” in thestationary plate is an expression having a meaning relative to the term“movable” used in the movable plate. “Stationary” means that thestationary plate functions as a reference point when the movable platerotates around the hinge shaft.

[0039] The rotation between the movable and stationary plates isperformed by rotating the movable plate relative to the stationary platearound the hinge member coupled to the movable and stationary plates,since the stationary plate coupled to the stand for the display forms afixed supporting point. The tilting angle of the display can be adjustedby the relative rotation. As will be described hereinafter, since thehinge member coupled to the movable and stationary plates is appliedwith compressive resilience in an axial direction from the resilientwasher, the movable and stationary plates are closely contacted to eachother, and thus the rotated position of the hinge member is maintained,even upon the relative rotation of the plates.

[0040]FIG. 3 is an exploded perspective view of the hinge assemblyaccording to the present invention. As shown in FIG. 3, the movableplate 10 secured to the rear side of the display of the flat paneldisplay appliance includes a horizontal portion arranged parallel to therear side of the display and a vertical portion arranged vertical to thehorizontal portion and having a through-hole 13 through which a hingeshaft is passed.

[0041] The stationary plate 20 coupled to the stand for the displayincludes a vertical portion arranged parallel to the vertical portion ofthe movable plate, and the vertical portion of the stationary plate hasa through-hole 23 through which the hinge shaft is passed.

[0042] In order to restrict the rotating range of the movable plate whenthe movable plate rotates relative to the stationary plate around thehinge shaft 30, the vertical portion of the movable plate 10 has a bentstopper boss 11 upwards of the through-hole 13. Also, the stationaryplate 20 may be provided with an arch stopper member 21 above thethrough-hole 23 for restricting a pivoting range B of the movable platecooperating with the bent stopper boss 11 of the movable plate 10. Anarched stopper member is provided along a pivoting radius of the bentstopper boss of the movable plate rotated relative to the stationaryplate 20 around the hinge shaft.

[0043] The hinge shaft 30 using common bolt is inserted into thethrough-holes of the movable and stationary plates, and a nut 70 isfastened to the threaded portion formed at one end of the hinge shaft,thereby completing the assembly of the hinge member. The hinge shaft hasa head portion and a cylindrical engaging portion having a diametersmaller than that of the head portion. The engaging portion has athreaded portion formed at one end thereof, and a nut is fastened to thethreaded portion.

[0044] The hinge shaft of the hinge member utilizes a common boltcomprising a hexagonal head portion 30 a and a threaded portion 30 b, sothat a faceting process including milling and turning required duringthe manufacturing of a conventional hinge assembly may be eliminated,thereby allowing for easy manufacturing of the hinge assembly which inturn decreases the manufacturing costs.

[0045] First and second washers 41 and 42 are interposed between thehead portion of the hinge shaft and the movable plate 10, and betweenthe stationary plate 20 and the nut 70, respectively, so as to securethe close fastening between the contacted components, to increasefrictional force and to decrease the wear of the contacted components.The first and second washers 41 and 42 may be flat washers, and have oilimpregnating grooves 41 a and 42 a. These oil impregnating grooves maybe formed at anyplace of a portion where a certain component becomes infrictional contact with another component, besides the first and secondwashers.

[0046] As described above, the rotation of the movable plate relative tothe stationary plate causes the contacted portion to be considerablyworn out. Accordingly, in order to solve the above problem, first andsecond stationary washers 51 and 52 are disposed at both sides of thethrough-hole of the movable plate, and third and fourth washers 53 and54 are disposed at both ends of the through-holes of the stationaryplate. These washers also serve as a function of fixedly securing thehinge shaft to the through-holes of the movable and stationary plates.

[0047] In order to fixedly engage the first and second stationarywashers 51 and 52 to the movable plate 10, the first and secondstationary washers 51 and 52 have bent bosses 51 a and 52 b formed alonga circumference of the respective washers, and the movable plate isformed with fixing holes 15 a and 15 b for receiving the bent bosses 51a and 52 b adjacent to the through-hole 13. If the bent bosses and thefixing holes correspond to each other, the number and position thereofmay be easily altered.

[0048] In order to fixedly engage the third and fourth stationarywashers 53 and 54 to the stationary plate 20, the third and fourthstationary washers 53 and 54 have bent bosses 53 a and 54 a formed alonga circumference of the respective washers, and the stationary plate isformed with fixing holes 25 a and 25 b for receiving the bent bosses 53a and 54 a adjacent to the through-hole 23. If the bent bosses and thefixing holes correspond to each other, the number and position thereofmay be easily altered. As the same reason, two stationary washersfixedly secured to both sides of any one of plates may be opposed toeach other.

[0049] Any one of the stationary washers 51, 52, 53 and 54 also servesas an elastic washer for applying axially compressive elasticity to thehinge assembly. The stationary washer is of a hemispheric or disc shape,and is biased in the direction of the hinge shaft by the fastening forceof the nut to securely maintain the engagement of the hinge member.

[0050] According to the embodiment of the present invention, the elasticwasher is applied to the fourth stationary washer 54, but any one of thefirst, second and third stationary washers 51, 52 and 53 may be replacedby an elastic washer 51′, 52′, or 53′ having a function of applyingcompressive elasticity to the hinge assembly in the axial direction. Ifthe fourth stationary washer 54 is applied as the elastic washer, thesecond washer 42 and the nut 70 positioned behind the fourth stationarywasher 54 may be replaced by an integrated washer-type nut 70′. Thesecond flat washer 42 is no further required by utilizing thewasher-type nut 70′ having a washer portion 70 a′, thereby reducing thenumber of components.

[0051]FIG. 4 shows a perspective view illustrating a hinge assembly fora flat panel display appliance according to another preferred embodimentof the present invention, in which a coil spring is installed. FIG. 5 isan exploded view of the hinge assembly shown in FIG. 4. As shown inFIGS. 4 and 5, the hinge assembly may include a coil spring member 60for adjusting the tilting angle of a large-size display in the directionof the nut 70 from the stationary plate 20. In the case of a heavy andbig display, since the hinge assembly is not securely positioned againstthe movable and stationary plates only by the fastening force of the nutand the compressive resilience of the elastic washer, the heavy displaymay be effectively supported by applying a resistive force in the pivotdirection using the spring member, when the movable plate rotatesrelative to the stationary plate (i.e., adjusting the tilting angle ofthe display).

[0052] In order to install the coil spring member 60, the movable plate10 has a latching groove 16 formed at the horizontal portion parallel tothe hinge shaft and receiving one end 60 b of the coil spring member 60.The other end 60 a of the coil spring member 60 is inserted into afixing hole 25 b formed at the stationary plate. At that time, thefixing hole 25 b of the stationary plate is also intended to receive thebent boss of the stationary washer.

[0053] According to an alternative embodiment of the present invention,the through-hole of the stationary plate may be replaced with an openedthrough-hole so as to easily assemble the hinge assembly. In this case,the hinge assembly may be installed through the opened portion of thestationary plate, thereby allowing easy assembly of the hinge assembly.

[0054] The hinge assembly employing the stationary plate with the openedthrough-hole is shown in detail in FIGS. 6 to 9.

[0055]FIGS. 6 and 7 are perspective and exploded views illustrating thehinge assembly for a flat panel display appliance, in which a coilspring is eliminated. As shown in FIGS. 6 and 7, the hinge assembly 100of the present invention includes a hinge member A, a movable plate 10fixed to a rear side of a display of the flat panel display appliancefor securing the hinge member A, and a stationary plate 20 coupled to astand supporting the display appliance against a certain bottom anddisposed adjacent to the movable plate to cause the movable plate to berotated.

[0056] The movable plate 10 secured to the rear side of the display ofthe flat panel display appliance includes a horizontal portion arrangedparallel to the rear side of the display and a vertical portion arrangedvertical to the horizontal portion and having a through-hole 13 throughwhich the hinge shaft is passed.

[0057] The stationary plate 20 coupled to the stand of the displayappliance includes a vertical portion parallel to the vertical portionof the movable plate. The vertical portion has a through-hole 23 ofwhich an upper portion is opened and which receives the hinge shaft 30through the opened portion. Generally, when assembling the hingeassembly, since the hinge shaft is mounted to the movable plate and thenthe stationary plate is installed, the stationary plate can be easilyinstalled from the bottom of the hinge shaft, in the state the hingeshaft is inserted into the movable plate. Specifically, it is easy tosecure the mounting space sufficient to install components of the hingeassembly upon the installation, thereby allowing for convenientinstallation of the hinge assembly.

[0058] In order to restrict the rotating range of the movable plate whenthe movable plate rotates relative to the stationary plate around thehinge shaft 30, the vertical portion of the movable plate 10 is formedwith a bent stopper boss 11 upwards the through-hole 13. Also, thestationary plate 20 may be provided with a partially arch stopper member21 above the opened through-hole 23 for restricting a pivoting range Bof the movable plate cooperating with the bent stopper boss 11 of themovable plate. The partially arch portion is provided along a pivotingradius of the bent stopper boss of the movable plate rotated relative tothe stationary plate 20 around the hinge shaft.

[0059] As described above, since the movable plate 10 rotates relativeto the stationary plate 20, one portion of the hinge member securelyengaged to the movable and stationary plates severely wears. In order toprevent the above wear, first and second stationary washers 51 and 52are disposed at both sides of the through-hole of the movable plate, andthird and fourth stationary washers 53 and 54 are disposed at both sidesof the through-hole of the stationary plate.

[0060] Any one of stationary washers, in particular, the third andfourth stationary washers 53 and 54 also serve as an axially fixingwasher for firmly fixing the hinge assembly which is coupled to thestationary plate to the through-hole 23 of the stationary plate 20, aswell as serving as the function of preventing the wear of the plate. Theterm “axially fixing washer” is a functional expression indicative offixing the hinge member to the stationary plate.

[0061] In order to fixedly engage the first and second stationarywashers 51 and 52 to the movable plate 10, the first and secondstationary washers 51 and 52 have bent bosses 5la and 52 b formed alonga circumference of the respective washers, and the movable plate isformed with fixing holes 15 a and 15 b for receiving the bent bosses 51a and 52 b adjacent to the through-hole 13. If the bent bosses and thefixing holes correspond to each other, the number and position thereofmay be easily altered.

[0062] In order to fixedly engage the third and fourth stationarywashers 53 and 54 to the stationary plate 20, the third and fourthstationary washers 53 and 54 have bent bosses 53 a and. 54 a formedalong a circumference of the respective washers, and the stationaryplate is formed with fixing holes 25 a and 25 b for receiving the bentbosses 53 a and 54 a adjacent to the through-hole 23. According to theshown embodiment of the present invention, the third stationary washer53 has one bent boss 53 a at an upper portion thereof, and the bent bossis adapted to insert into the opened portion of the through-hole 23. Awidth “A” of the bent portion of the bent portion 53 a almostcorresponds to that of the opened portion of the through-hole 23 of thesecond plate.

[0063] The third stationary washer 53 may further include a bent boss(not shown) fixedly engaged to a lower fixing hole 25 b of the secondplate. If the bent bosses and the fixing holes correspond to each other,the number and position thereof may be easily altered. As the samereason, two stationary washers fixedly secured to both sides of any oneof plates may be opposed to each other.

[0064] At least one of the stationary washers 51, 52, 53 and 54 alsoserves as an elastic washer for applying axially compressive elasticityto the hinge assembly. The stationary washer is of a hemispheric or discshape, and is biased in the direction of the hinge shaft by thefastening force of the nut to securely maintain the engagement of thehinge member.

[0065] According to the embodiment of the present invention, the elasticwasher is applied to the fourth stationary washer 54, but any one of thefirst, second and third stationary washers 51, 52 and 53 may be replacedby an elastic washer 51′, 52′, or 53′ having a function of applyingcompressive elasticity to the hinge assembly in the axial direction.

[0066] If the fourth stationary washer 54 is applied as the elasticwasher, the second washer 42 and the nut 70 positioned behind the fourthstationary washer 54 may be replaced by an integrated washer-type nut70′. The second flat washer 42 is no further required by utilizing thewasher-type nut 70′ having a washer portion 70 a′, thereby reducing thenumber of components.

[0067] Components of the hinge assembly shown in FIGS. 6 and 7, but notdescribed herein, have the same function as that described in theembodiment of FIGS. 2 and 3

[0068]FIG. 8 shows a perspective view illustrating a hinge assembly fora flat panel display appliance according to another preferred embodimentof the present invention, in which a coil spring is installed. FIG. 9 isan exploded view of the hinge assembly shown in FIG. 8. The hingeassembly may include a coil spring member 60 for adjusting the tiltingangle of a large-size display in the direction of the nut 70 from thestationary plate 20. In the case of a heavy and big display, since thehinge assembly is not securely positioned against the movable andstationary plates by the fastening force of the nut and the compressiveresilience of the elastic washer, the heavy display may be effectivelysupported by applying a resistive force in the pivot direction, when themovable plate rotates relative to the stationary plate (i.e., adjustingthe tilting angle of the display).

[0069] In order to install the coil spring member 60, the movable plate10 has a latching groove 16 formed at the horizontal portion parallel tothe hinge shaft and receiving one end 60 b of the coil spring member 60.The other end 60 a of the coil spring member 60 is inserted into thefixing hole 25 b formed at the stationary plate. At that time, thefixing hole 25 b of the stationary plate is also intended to receive thebent boss of the stationary washer or the axially fixing washer.

[0070] Components of the hinge assembly shown in FIGS. 8 and 9 but notdescribed herein have the same function as that described in theembodiment of FIGS. 6 and 7

[0071] While the present invention has been described and illustratedherein with reference to the preferred embodiments thereof, it will beapparent to those skilled in the art that various modifications andvariations can be made therein without departing from the spirit andscope of the invention. Thus, it is intended that the present inventioncovers all modifications and variations of this invention that comewithin the scope of the appended claims and their equivalents.

INDUSTRIAL APPLICABILITY

[0072] With the above description, the present invention provides ahinge assembly adapted to be easily assembled using a common bolt,without separately machining a hinge shaft of a basic axis around whicha display is pivoted. In addition, the hinge assembly is adapted so thatthe stationary and movable plates are not worn out when they rotate.Also, the hinge assembly can adjust the tilting angle of the display,without using a separate component assembled to the faceted hinge shaftso as to restrict the pivoting range of the hinge shaft. Furthermore,the present invention can provide a pivot assembly which has excellentpivotable performance capable of being easily assembled and reducing themanufacturing cost thereof.

1. A hinge assembly for adjusting a tilting angle of a display for aflat panel display appliance, comprising: a movable plate fixed to arear side of the display and having a through-hole; a stationary platecoupled to a stand for the display appliance and having a through-hole;a hinge shaft passing through the through-holes of the movable andstationary plates and having a head portion; a coupling member fixed toone end of the hinge shaft; a first washer disposed between the headportion of the hinge shaft and the movable plate; first and secondstationary washers disposed at both sides of the through-hole of themovable plate; and third and fourth stationary washers disposed at bothsides of the through-hole of the stationary plate; wherein at least oneof the first, second, third and fourth stationary washes is an elasticwasher for applying compressive elasticity to the hinge shaft in anaxial direction.
 2. The hinge assembly as claimed in claim 1, whereinthe through-hole of the stationary plate is opened at an upper portionthereof.
 3. The hinge assembly as claimed in claim 1, wherein themovable plate has a bent boss at an upper end of the through-hole, andthe stationary plate has a pivot guide having a certain pivot range atan upper end of the through-hole, the bent boss of the movable platemoving along the pivot guide so as to pivot about the hinge shaft. 4.The hinge assembly as claimed in claim 1, wherein the movable plate hasa latching groove formed at a portion parallel to the hinge shaft, and acoil spring with one end fixed to the latching groove of the movableplate and the other end fixed to a fixing hole formed at the stationaryplate, the coil spring applying a resistant force against a pivotingdirection of the movable plate relative to the stationary plate aroundthe hinge shaft.
 5. The hinge assembly as claimed in claim 1, whereinthe first, second, third and fourth stationary washers have at least onefixing boss, and the movable and stationary plates are formed with afixing hole adjacent the through-hole thereof for receiving the fixingboss of the stationary washer.
 6. The hinge assembly as claimed in claim2, wherein any one of the third and fourth stationary washers has anupper fixing boss of a width slightly smaller than that of the openedportion of the through-hole of the stationary plate, and the fixing holeof the stationary plate for receiving the upper fixing boss is theopened portion of the through-hole.
 7. The hinge assembly as claimed inclaim 1, wherein the hinge shaft has an axially extended portion with athreaded portion formed thereon, and a head portion larger in diameterthan the extended portion.
 8. The hinge assembly as claimed in claim 7,wherein the hinge shaft is a commonly used bolt.
 9. The hinge assemblyas claimed in claim 1, wherein the coupling member is a nut.
 10. Thehinge assembly as claimed in claim 1, wherein the first washer is a flatwasher.
 11. The hinge assembly as claimed in claim 10, wherein the firstwasher has an oil impregnating groove for preventing wear of a contactedportion between the washers and an adjacent component and for securingsmooth pivoting movement.
 12. The hinge assembly as claimed in claim 1,wherein at least one of the stationary washers has an oil impregnatinggroove for preventing wear of a contacted portion between the washersand an adjacent component and for securing smooth pivoting movement. 13.The hinge assembly as claimed in claim 1, wherein the elastic washer isa hemispheric washer having a fixing boss fixed to the plate.
 14. Thehinge assembly as claimed in claim 13, wherein the elastic washer is astationary washer fixed to the stationary plate and disposed adjacent tothe coupling member, and the coupling member is a washer-type nut.